Overcharging?

Charlie_Boy7

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My wifes 98 v6 camaro shows the voltage after 18 in the red. Read online that it was the regulator in the alternator. So i changed that out.. no change. What do i test next? I hope i still have my voltmeter still lying around somewhere
 

Charlie_Boy7

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Thats what i was starting to think. How do i test that.. just put the leads on the battery while its running?
 

Sprayin

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That's one way, but doesn't tell you much besides whether or not there is an issue.
 

1quick

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test the positive pole on the alt that will tell you what its actually putting out
 

1quick

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while its running so you can see the full output
 

Charlie_Boy7

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Okay cool thanks. I'll try to get back at it tomorrow and see what's up. If it is in fact the gauge would swapping out the cluster fix that?
 

1quick

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it should or you just dont pay attention to the gauge, most factory gauges are off by a little anyway
 

Great White Drake

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Be careful, I had a battery explode because of overcharging.
 

P40E

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All you have to do is put a volt meter on the battery posts while the engine is running and check to see what it's at at idle . And then hold the throttle a little and see if it goes up any . The volts should be around 14 .

If you dont have one you can go to auto zone and they will put a tester on it in the parking lot for free I believe , or one of those stores like it . If they try to sell you something just say you gotta check your money situation first . Then leave .

If you dont have a tester you can probably go to harbor freight and buy the cheapest one they got . It's like 2.99 lol .All you are doing is checking volts . Does not have to be expensive.
 

bikrboy128

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it's an old GM, the gauge is probably broken. what does it read with key on engine off? at 18 volts you would have a battery meltdown along with other electrical problems. grab a volt meter and put it on the battery to make sure
 

rocket5979

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test the positive pole on the alt that will tell you what its actually putting out
There will be no advantage to testing the voltage directly at the alternator versus at the battery terminals. Either way the voltage will read exactly the same; short of an immense (aka fire-worthy) resistance exhibited in the lead wire between the alt and battery.

Resting voltage should be around 12.5 volts. Running voltage will usually be between 13.5 - 14.5 volts.
 

Turbocharged400sbc

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thats sorta false, measuring the two points will give you a voltage drop reading across the ground path, which is entirely usefull for diagnostic purposes, esp if the pcm uses the batt ground as the voltage ref point or the block sensor ground.

knowing what the batt, alt and pcm voltage/ground readings are is quite the advantage when starting out with this sort of a diagnostic issue.
leaving a gap in the routine/info is just shooting yourself in the foot
 

rocket5979

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thats sorta false, measuring the two points will give you a voltage drop reading across the ground path, which is entirely usefull for diagnostic purposes, esp if the pcm uses the batt ground as the voltage ref point or the block sensor ground.

knowing what the batt, alt and pcm voltage/ground readings are is quite the advantage when starting out with this sort of a diagnostic issue.
leaving a gap in the routine/info is just shooting yourself in the foot

I disagree when it comes to just doing a quick test. When doing a spot check to see if his voltage is indeed entirely too high compared to his gauge, measuring at the battery is totally fine. Sure, enough resistance in the wiring between the alt and batt will cause a voltage drop, but unless said power wire is really screwed then it will be a non-issue. A ballpark spot check is all that is needed for quick verification. If the OP receives a reading that is out of the norm, then take the time to dig a little deeper. No need to jump in the deep end first, when it may not even be needed.
 

Charlie_Boy7

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I believe when its on and not running it slowly climbs a bit but nothing crazy. I found my old voltmeter from school but didn't get a chance to test it since i took my daughter to the ER this morning
 

Charlie_Boy7

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Everything tested normal on the voltmeter so i guess it was the gauge. The very next day I drove it the wheel bearing went and i wasn't getting heat in the cabin either.

So it pissed me off and i sold it. Oh well.. I'll just be Trans Am hunting when i get to Texas. Thanks for the help it's always appreciated
 

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